The present invention relates to on electrical connection device comprising a catch for fastening to a support rail.
The electrical connection device is for example a terminal block or a fuse holder. When the device to be mounted is relatively small in size, the fastening to the support rail is effected for example by snap-engagement. Such fastening is suitable since the force required to carry out this fastening is relatively small. For electrical devices of larger sizes, a maneuverable latching system also referred to as a fastening catch is used.
The support rails used are profiled rails exhibiting a U-shaped cross section. The free end of the branches of the U is folded back substantially at right angles toward the outside and thus forms two lateral wings. The known fastening catches generally comprise two hooks, one at least of which is moveable, each intended to grasp a lateral wing from below.
The documents EP-0 326 624 and DE-41 08 072 disclose for example such a fastening catch.
With these fastening catches one has an access problem. Specifically, it is sometimes difficult within an electrical cabinet to access the fastening catch in order to carry out latching or unlatching on the support rail. Another drawback of these fastening catches is that they are always prestressed in the latching position. This does not facilitate their mounting on the support rail.
The aim of the present invention is to provide an electrical connection device comprising a fastening catch allowing latching and unlatching on a support rail which is more readily accessible and preferably easier than for the devices of the prior art.
To this end, it proposes an electrical connection device comprising a catch for fastening to a support rail disposed in an insulating housing, the fastening catch comprising two relatively sliding pieces and each piece exhibiting a hook intended to allow latching on the support rail.
According to the invention, a central hole substantially perpendicular to the direction of movement of the sliding pieces of the fastening catch is made in the housing so as to allow access to the fastening catch from the top of the housing, and in the latched position of the hooks, an edge running transversely with respect to the direction of movement of the hooks of each piece is located in line with the central hole. In this way, it is possible to access the fastening catch from the top of the housing which is always accessible. It is sufficient to slip a flat screwdriver between the two edges of the sliding pieces and by rotating the screwdriver by 90xc2x0 or more the sliding pieces are parted from one another.
The edge of each piece located in line with the central hole is advantageously beveled, so that in the mounted state of the catch, the two beveled edges face one another. This facilitates the introduction of a tool, for example a screwdriver blade, so as to act on the sliding pieces.
The two sliding pieces are preferably identical and they each exhibit the form of two elongate plates disposed one along the extension of the other with a heightwise offset, a lateral notch allowing the nesting of the two sliding pieces being provided substantially in the middle of each sliding piece. In this way, the cost price of the fastening catch is substantially reduced.
In one embodiment, each sliding piece comprises an elastic blade running perpendicularly to the direction of movement of the sliding pieces toward the inside of the housing and intended to bear against an inside wall of this housing in such a way as to prestress each sliding piece toward the latching position. There is thus no need to provide a separate restoring spring. These elastic blades run for example along the central hole.
To obtain a fastening catch which is stable in the unlatched position, a first sliding piece exhibits snap-engagement means and the second sliding piece comprises complementary snap-engagement means so that these snap-engagement means. cooperate when the sliding pieces are in the unlatched position and possibly also in the latched position.
One embodiment then provides for the first sliding piece to comprise a second hook mounted elastically in a direction substantially perpendicular to the direction of movement of the sliding pieces and for the second sliding piece to comprise two grooves intended to receive the end of the second hook. The latter is for example disposed at the end of an elastic dog cut out from the sliding piece.
So as also to be able to act on the fastening catch via the edges of the connection device, a variant embodiment provides for the two sliding pieces to overlap, for a sliding piece to comprise at one of its ends a recess intended to receive the blade of a screwdriver and for an end of the other sliding piece to exhibit at the height of the recess a raised rim intended to serve as bearing for the screwdriver.